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Title: Electron acceleration during the decay of nonlinear Whistler waves in low-beta electron-ion plasma

Relativistic electron acceleration through dissipation of a nonlinear, short-wavelength, and monochromatic electromagnetic whistler wave in low-beta plasma is investigated by utilizing a one-dimensional fully relativistic electromagnetic particle-in-cell code. The nonlinear (large-amplitude) parent whistler wave decays through the parametric instability which enhances electrostatic ion acoustic waves and electromagnetic whistler waves. These waves satisfy the condition of three-wave coupling. Through the decay instability, the energy of electron bulk velocity supporting the parent wave is converted to the thermal energy perpendicular to the background magnetic field. Increase of the perpendicular temperature triggers the electron temperature anisotropy instability which generates broadband whistler waves and heats electrons in the parallel direction. The broadband whistler waves are inverse-cascaded during the relaxation of the electron temperature anisotropy. In lower-beta conditions, electrons with a pitch angle of about 90° are successively accelerated by inverse-cascaded whistler waves, and selected electrons are accelerated to over a Lorentz factor of 10. The result implies that the nonlinear dissipation of a finite-amplitude and short-wavelength whistler wave plays an important role in producing relativistic nonthermal electrons over a few MeV especially at lower beta plasmas.
Authors:
;  [1] ;  [2]
  1. Solar-Terrestrial Environment Laboratory, Nagoya University, Nagoya City, Aichi 464-8601 (Japan)
  2. Faculty of Human Development, University of Toyama, Toyama City, Toyama 930-8555 (Japan)
Publication Date:
OSTI Identifier:
22370461
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 794; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; ANISOTROPY; COUPLING; DECAY; DECAY INSTABILITY; ELECTRON TEMPERATURE; ELECTRONS; ION ACOUSTIC WAVES; IONS; LOW-BETA PLASMA; MAGNETIC FIELDS; MEV RANGE; MONOCHROMATIC RADIATION; NONLINEAR PROBLEMS; PARAMETRIC INSTABILITIES; RELATIVISTIC RANGE; RELAXATION; VELOCITY; WAVELENGTHS; WHISTLERS